Thermal food tray

ABSTRACT

A tray for handling food in a warming oven comprises a dish portion a rim portion and a gasket portion. The dish portion is constructed from a first material and has a base portion adapted for handling of food products. The dish also has a wall portion surrounding the entirety of the base portion and extending therefrom. The wall portion has a closed end connected to the base portion and an open end disposed away from the base portion. The rim portion is constructed from a second material and extends generally parallel to the wall portion, around the perimeter of the dish portion. The rim portion has an attached end adapted for compressive engagement with the open end of the wall and a free end adapted to facilitate handling of the tray. The gasket is compressively disposed between the dish and the rim and adapted to restrict the movement of the dish away from the rim.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/749,931, filed Dec. 13, 2005.

FIELD OF THE INVENTION

The invention relates to apparatus for keeping food warm between thetime of preparation and service.

BACKGROUND

Warming ovens are used in the food service industry to keep food warmbetween the time of preparation and the time of service. Traysconstructed of plastic are presently used because of their ease ofhandling, and their durability. When kept in the warming oven, however,it is sometimes preferable that food is in contact with metal surfaces,such as aluminum or stainless steel, rather than plastic or othernon-metal materials. Metals, however, are subject to deformation and thedevelopment of sharp edges because of wear and tear. Further, whenstored at elevated temperature conditions, metal tends to become hot tothe touch, thereby making the tray difficult to handle. Accordingly, itis desirable to produce a tray that has the food storage characteristicsof metal while having properties of materials that are easier to handleat elevated temperature conditions.

SUMMARY OF THE INVENTION

This invention relates to apparatus for keeping food warm between thetime of preparation and service. Specifically, the invention relates toa tray for retaining food products in warming ovens or otherenvironmentally controlled devices.

One aspect of the present invention is a tray having a dish portion, arim portion and a gasket portion. The dish is constructed from a firstmaterial and includes a base portion adapted for handling food products.The dish also includes a wall portion surrounding the entirety of thebase portion and extending upwardly therefrom to define a retainingarea. The retaining area is closed by the base portion at the bottom endof the wall and opens away from the base portion at the upper end of thewall. The rim is constructed from a second material and has an inner lipthat extends generally parallel to the wall portion of the dish. Theinner lip is secured around the perimeter of the wall of the dish. Therim is attached to the wall by a compressive engagement. The rim alsohas a free end for handling of the tray. The gasket is compressivelydisposed in the lip and forms the compressive bond between the dish andthe rim.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the invention, there is shown in thedrawings a form, which is presently preferred; it being understood, thatthis invention is not limited to the precise arrangements andinstrumentalities shown.

FIG. 1 is a perspective view of a tray according to an embodiment of thepresent invention.

FIG. 2 is a second perspective view of the tray shown in FIG. 1.

FIG. 3 is a cross-sectional view of the tray shown in FIG. 1.

FIG. 4 is a cross-sectional view of a portion of the tray shown in FIG.1, detailing the attachment of a dish to a rim.

FIG. 5 is a cross-sectional view of a tray according to an embodiment ofthe present invention.

FIG. 6 is a cross-sectional and perspective view of the tray shown inFIG. 4.

FIG. 7 is a cross-sectional view of a gasket for use in a trayembodiment of the present invention.

FIG. 8 is a perspective view of the gasket shown in FIG. 6.

FIG. 9 is a cross-sectional view of a portion of the tray shown in FIG.4.

FIG. 10 is a side elevational view of tray shown mounted within awarming oven.

DETAILED DESCRIPTION OF THE DRAWINGS

It will be appreciated that the following description is intended torefer to specific embodiments of the invention selected for illustrationin the drawings and is not intended to define or limit the invention,other than in the appended claims.

In the Figures, in which like reference numerals indicate like elements,there is shown an embodiment of a tray for use in warming ovens, such asthose commonly used in fast food restaurants. The tray, which isidentified generally by the numeral 10, may be used to store food in anorderly and easily accessible manner while the food waits in a warmingoven (not shown) or other environmental control device prior to service,further preparation or processing. For purposes of this disclosure, thedirections up and down, will refer respectively to those directions whenviewed in FIG. 1.

The warming oven may be used in a fast food restaurant to hold preparedfood between the time of preparation and the time of serving. It ispreferable that the warming oven keep the food in a ready-to-eat state.Temperatures inside the warming oven may reach levels above 180 degreesFahrenheit. It is also desirable to regulate the humidity within theoven to ensure that the food does not become dried out or soggy. A trayfor use in such ovens must be constructed from materials that willwithstand the conditions within the oven, as well as other storage andcleaning conditions. Further, because the tray is used in the foodservice industry, it is preferable that the materials and constructionmeet the guidelines of the National Sanitation Foundation (NSF) for suchapparatus.

Referring to FIGS. 1-3, the tray 10 as illustrated includes a dishportion 20, a rim portion 40 and a gasket 60. The gasket 60 is disposedbetween the dish 20 and the rim 40 for compressive engagement of thedish 20 and rim 40 to form the tray 10.

The dish 20 includes a generally rectangular base 22 defining the bottomof the tray 10. Preferably, the length of the tray 10 is about two feetand the width W is sufficient to accommodate the food item that is to becontained therein, such as a hamburger patty. The base 22 is generallyflat and has an inner surface 30 and an outer surface 32. A sidewall 24extends upwardly from the perimeter of the base 22. The sidewall 24 andthe base 22 are preferably of unitary construction, and define theretaining area of the dish 20. One or more ridges 26 may be providedlongitudinally along the base 22. The ridges 26 are generally raisedabove the remainder of the inner surface 30 and support the food (notshown) above the remainder of the inner surface 30 of the base 22,thereby forming a passageway under the food for circulation of heatedair or allow for the drainage of juices from the food. Those skilled inthe art will recognize that although longitudinal ridges 26 are shown,lateral ridges or some pattern or ridges, bumps or other features may bedisposed on the base without departing from the scope of the presentinvention.

The wall 24 preferably surrounds the base portion 22. The joint betweenthe wall 24 and the base 22 is curved. The retaining area is closed bythe base 22 at the bottom and is open at the upper end 24 b along thetop edge of the wall 24. As illustrated, the wall 24 extends generallyperpendicular to the base 22. However, the wall may also extendoutwardly and upwardly from the base, or have other features withoutdeparting from the scope of the present invention.

The rim portion 40 extends around the perimeter of the dish 20.Preferably, the rim 40 comprises a vertical section 42 having an upperportion 43 and a lower portion 44. The lower portion 44 has an innerwall 44 a and an outer wall 44 b. A retaining channel 45 (FIG. 4) ispreferably disposed between the inner and outer walls 44 a, 44 b. Aswill be described in further detail below, the retaining cavity 45 isadapted to receive the open end 24 b of the wall 24 for securing the rim40 to the dish 20.

Referring now to FIGS. 1-6, the upper portion 43 of the vertical section42 of the rim 40 extends upwardly from the lower portion 44. A pluralityof apertures 47 may be provided through the upper portion 43 tofacilitate circulation of air into the tray 10. Outer rim 48 extendsoutwardly along the longitudinal sides of the rim 40. The outer rims 48preferably have a generally arcuate cross section with a rounded convextop surface 48 a and a generally concave bottom surface 48 b. In someexamples of the tray 10, the bottom surface 48 b may be sized tofacilitate the mounting of the tray 10 on rails disposed within theoven. Those skilled in the art will recognize that a variety ofconfigurations may be used to facilitate mounting of the tray in an ovenwithout departing from the scope of the present invention.

Mounting end portions 52 are preferably disposed at longitudinal ends ofthe rim 40. The mounting ends 52, like the outer rims 48 preferablyfacilitate the mounting of the tray 10 inside of a warming oven. Themounting ends 52 extend across the width W of the tray 10 and havedownwardly depending corner portions 53. The corner portions 53 arehollow, and are open on top to facilitate grasping the trays 10. Slots54 are also provided in the mounting ends 52 and define a resilient tabfor engagement of the tray 10 by an oven structure (not shown), forretention of the tray 10 in the oven.

A gasket 60 is disposed between the dish 20 and the rim 40 and adaptedto resiliently secure the rim 40 to the dish 20. As best seen in FIGS.3-9, the gasket 60 preferably has an inverted, generally U-shaped crosssection with an upper portion 62 and outer walls 64 extending downwardlytherefrom. Internal ribs 66 extend inwardly and upwardly into thecentral portion of the U-shape. The internal ribs 66 facilitate theinsertion of the upper end 24 b of the wall 24 into the gasket 60 andthen resist the withdrawal of the wall 24 therefrom. Outer ribs 68 aredisposed on the outer surface of the gasket 60. The outer ribs 68preferably extend outwardly and downwardly from the gasket wall in amanner that facilitates the insertion of the gasket 60 into theretaining cavity 45 formed by the inner and outer walls 44 a, 44 b ofthe rim 40 and restricts the movement of the gasket 60 therefrom.

During assembly, the gasket 60 is disposed about the dish portion 20 byinserting the open end 24 b of the wall 24 between the outer walls 64 ofthe gasket 60. One wall 64 is preferably disposed on the inside of thedish 20, while a second wall 64 is preferably disposed on an outside ofthe dish 20. The inner ribs 66 preferably engage the open end 24 b andare pressed upwardly as the open end 24 b is slid into the gasket 60.The angle of the inner ribs 66 preferably restricts the movement of thegasket 60 away from the dish 20, once the open end 24 b is inserted inthe gasket 60. It is preferable that the engagement between the gasket60 and the dish 20 is tight, providing a snug fit between the two pieces60, 20. The wall 24 of the dish 20 may also be textured, bent, curled orthe like to increase frictional engagement with the gasket 60 and toresist the disassembly of the tray 10.

After attachment of the gasket 60 to the dish 20, the gasket 60 is theninserted into the retaining cavity 45 of the rim 40. The outer ribs 68are shown as angled to facilitate the insertion of the gasket 60 intothe cavity 45 by allowing the inner and outer walls 44 a, 44 b to slidealong the ribs 68 while pushing them towards the gasket 60. The ribs 68may take other forms, such as being straight or including a chamfer, soas to increase retention of the gasket 60 in the cavity 45. Like theinner ribs 66, the angle of the outer ribs 68 restricts the movement ofthe gasket 60 out of the cavity 45 once the gasket 60 is insertedtherein. The cavity 45 is preferably sized to compress the gasket 60between the first and second walls 44 a, 44 b and the open end 24 b ofthe dish wall 24. The deformation of the ribs 66, 68 and thecompressable nature of the material of the gasket 60 allows the gasket60 to resiliently retain the rim and the dish together. It is preferablethat the gasket 60 allow for thermal expansion of the dish 20 and therim 40, while still maintaining a seal between the two parts 20, 40.

The dish 20 is preferably constructed from a metal. Examples of suchmetals are stainless steel, titanium and aluminum, with aluminum beingthe preferred material. It is also preferable that the rim 40 beconstructed of a plastic material of the type generally adapted to beused in temperature and variable humidity conditions of a foodpreparation and warming oven, without corrosion, deformation or reactionwith surrounding materials. The gasket 60 is preferably constructed froma material that maintains a seal between the dish 20 and the rim 40 inheated conditions, as well as at room temperature and in colderenvironments, such as refrigerators or freezers. The gasket 60 ispreferably adapted to accommodate a ratio of thermal expansion of 10 to1 between the plastic of the rim 40 and the metal of the dish 20,respectively. In other words, the plastic of the rim 40 may expand up to10 times more than the metal of the dish 20 at certain temperatures.Higher ratios of expansion are also contemplated without departing fromthe scope of the present invention. The gasket 60 should maintain a sealafter repeated use and cleaning of the tray. Such a material should alsobe resistant to corrosion and hardening after exposure to chemicals usedin cleaning, as well as exposure to food products in a variety oftemperature and humidity conditions. As mentioned above, it ispreferable that the materials and construction used meet the NSFguidelines for food service devices.

In a preferred embodiment of the tray 10, the seal is maintained betweenthe dish 20 and the rim 40 in a variety of thermal states. For example,in a first state, such as when the tray is inside of the oven andmaintained at an elevated temperature, the rim 40 may be expanded insuch a way that the wall 64 of the gasket adjacent to wall 44 a of therim 40 experiences an increase in compression between the wall 24 of thedish 20 and the inner wall 44 a. The compression of the inside gasketwall 64 occurs because the plastic material of the rim 40 will normallyexpand at a greater rate or amount than the metal of the dish 20 whenboth are heated. Correspondingly, in a second state, the seal ismaintained by the compression of the wall 64 of the gasket 60 betweenthe outer wall 44 b of the rim 40 and the wall 24 of the dish 20. Thissecond state of thermal expansion occurs at a temperature that is coolerthan that discussed above for the first state, such as when the tray isat a temperature that is cooler than ambient room temperature. It isalso preferable that during the transition between the first and secondstates of thermal expansion, the seal is maintained by the compressionof at gasket between the first and second walls 44 a, 44 b and the dish20.

Referring now to FIG. 10, in use, the tray 10 is placed within an oven70. The oven 70 is a traditional warming oven with front and rear doors72, 74. While the tray 10 is within the oven 70, heat is readilytransferred through the metal dish portion 20, and is less readilytransferred through the rim 40. In instances where food is prepared onone side of the oven 70 and served (or further prepared) on the otherside of the oven 70, the tray 10 may inserted through the first door 72and slid across the bottom 76 of the oven 70. The tray 10 may then beremoved using the second door 74. Alternatively, the slots 54 (not shownin FIG. 10) facilitate the engagement of the tray 10 with acorresponding oven structure (not shown), indicating to a user that thetray 10 is in its proper position within the oven 70.

While a press fit between the dish 20 and the rim 40, with the gasket 60disposed therebetween, is the preferred method of construction, othermethods may be used contemplated without departing from the scope of thepresent invention. Regardless of the assembly method, it is desirablethat a gasket is utilized between the dish and the rim to simplify themanufacturing process, to maintain a seal and to secure the dish to therim.

A variety of modifications to the embodiments described will be apparentto those skilled in the art from the disclosure provided herein. Thus,the invention may be embodied in other specific forms without departingfrom the spirit or essential attributes thereof and, accordingly,reference should be made to the appended claims, rather than to theforegoing specification, as indicating the scope of the invention.

1. A tray for handling food in a warming oven comprising: a dish,constructed from a first material, having a base portion adapted forhandling of food products, and a wall portion surrounding the entiretyof the base portion and extending upwardly therefrom, the wall portionhaving a lower edge connected to the base portion and an upper edgedisposed away from the base portion; a rim, constructed from a secondmaterial, the rim having a lower edge adapted for engagement with theopen end of the wall portion and a free end adapted to facilitatehandling of the tray; and a gasket compressively disposed between thedish and the rim and adapted to resiliently secure the dish and the rim.2. The tray according to claim 1, wherein the first material is a metal.3. The tray according to claim 1, wherein the second material is aplastic.
 4. The tray according to claim 1, wherein the base portioncomprises at least one ridge extending along at least a portion thereof.5. The tray according to claim 1, the tray further comprising a firstend and a second end disposed longitudinally away from the first end,each of the first and second ends having a gripping tab portionextending longitudinally therefrom.
 6. The tray according to claim 1,the free end of the rim having at least one mounting tab extending alonga lateral portion thereof.
 7. The tray according to claim 1, wherein oneof the lower edge of the rim and the upper edge of the dish has a firstwall, a second wall, and an attachment cavity disposed between the firstand second walls.
 8. The tray according to claim 1, wherein the gaskethas a generally U-shaped cross-sectional profile, having an innerportion and an outer portion, wherein each portion is adapted forengagement with one of the upper edge of the wall portion of the dishand the lower edge of the rim.
 9. The tray according to claim 8, thegasket further comprising at least one retaining rib extending therefromfor engagement with one of the upper edge of the wall portion of thedish and the lower edge of the rim.
 10. The tray according to claim 9,wherein the retaining rib is angled to facilitate movement of the gasketwith respect to a portion of the tray in a first direction and restrictthe movement of the gasket with respect to said portion in an opposingsecond direction.
 11. The tray according to claim 8, wherein the upperedge of the wall of the dish is insertable into the inner portion of thegasket.
 12. The tray according to claim 11, wherein the outer portion ofthe gasket is compressively insertable into the attachment cavity of therim, for retainment therein.
 13. The tray according to claim 1, whereinthe wall portion is generally perpendicular to the base portion.
 14. Atray for handling food in a warming oven comprising: a dish constructedfrom a first material having a peripheral wall with inner and outerfaces; a rim constructed from a second material having a peripheralcavity defined by inner and outer rim walls, the second material havinga greater coefficient of thermal expansion than the first material; anda generally U-shaped gasket constructed from a resilient material,having a first gasket portion and a second gasket portion disposed onthe peripheral wall with the first gasket portion disposed adjacent tothe inner face and the second gasket portion disposed adjacent to theouter face; wherein the rim disposed about the gasket and the peripheralwall with the inner rim wall disposed proximate the first gasket portionand the outer rim wall disposed proximate the second gasket portion; andwherein a seal is formed between the inner wall and the inner face ofthe peripheral wall, in conjunction with or separately from the outerwall and the outer face of the peripheral wall, due to compression ofthe first and second gasket portions therebetween and at various statesof thermal expansion of the materials.